Several early studies and much recent evidence demonstrate that both indicators and potentially pathogenic bacteria are capable of differential and extended survival in marine waters and sediments. At Guam, fecal coliforms, fecal streptococci, Escherichia coli, Klebsiella pneumoniae, several Vibrio spp., and (by inference) potential pathogens can be found in sediments underlying the recreational waters that public health monitoring agencies routinely find to be free of indicators. The proposed research will involve undergraduate and graduate students in exploratory and experimental research on the diversion of contaminated runoff into ponding basins and percolation fields that recharge groundwaters that rapidly (within hours) delivery Escherichia coli, Klebsiella pneumoniae, Pseudomonas aeruginosa, Vibrio spp., Candida albicans, and fecal streptococci to coastal recreational waters and sediments. A variety of techniques (e.g., fluorescent respiratory stains and antibodies) will be used to tag, trace, enumerate, and measure the occurrence of these organisms in runoff, their transport through sewerage diversions, and their accumulation, possible growth, and the survival of these organisms in sediments. The work will help describe a presently unacknowledged and unacceptable risk to recreational water users.